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improve DLC parameters

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This commit is contained in:
Gilles Boccon-Gibod
2024-06-03 18:11:13 -07:00
parent f2dc8bd84e
commit f5baf51132
4 changed files with 204 additions and 78 deletions
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107
bumble/rfcomm.py
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@@ -106,9 +106,11 @@ CRC_TABLE = bytes([
0XBA, 0X2B, 0X59, 0XC8, 0XBD, 0X2C, 0X5E, 0XCF
])
RFCOMM_DEFAULT_L2CAP_MTU = 2048
RFCOMM_DEFAULT_WINDOW_SIZE = 7
RFCOMM_DEFAULT_MAX_FRAME_SIZE = 2000
RFCOMM_DEFAULT_L2CAP_MTU = 2048
RFCOMM_DEFAULT_INITIAL_CREDITS = 7
RFCOMM_DEFAULT_MAX_CREDITS = 32
RFCOMM_DEFAULT_CREDIT_THRESHOLD = RFCOMM_DEFAULT_MAX_CREDITS // 2
RFCOMM_DEFAULT_MAX_FRAME_SIZE = 2000
RFCOMM_DYNAMIC_CHANNEL_NUMBER_START = 1
RFCOMM_DYNAMIC_CHANNEL_NUMBER_END = 30
@@ -365,12 +367,12 @@ class RFCOMM_MCC_PN:
ack_timer: int
max_frame_size: int
max_retransmissions: int
window_size: int
initial_credits: int
def __post_init__(self) -> None:
if self.window_size < 1 or self.window_size > 7:
if self.initial_credits < 1 or self.initial_credits > 7:
logger.warning(
f'Error Recovery Window size {self.window_size} is out of range [1, 7].'
f'Initial credits {self.initial_credits} is out of range [1, 7].'
)
@staticmethod
@@ -382,7 +384,7 @@ class RFCOMM_MCC_PN:
ack_timer=data[3],
max_frame_size=data[4] | data[5] << 8,
max_retransmissions=data[6],
window_size=data[7] & 0x07,
initial_credits=data[7] & 0x07,
)
def __bytes__(self) -> bytes:
@@ -396,7 +398,7 @@ class RFCOMM_MCC_PN:
(self.max_frame_size >> 8) & 0xFF,
self.max_retransmissions & 0xFF,
# Only 3 bits are meaningful.
self.window_size & 0x07,
self.initial_credits & 0x07,
]
)
@@ -450,17 +452,21 @@ class DLC(EventEmitter):
self,
multiplexer: Multiplexer,
dlci: int,
max_frame_size: int,
window_size: int,
tx_max_frame_size: int,
tx_initial_credits: int,
rx_max_frame_size: int,
rx_initial_credits: int,
) -> None:
super().__init__()
self.multiplexer = multiplexer
self.dlci = dlci
self.max_frame_size = max_frame_size
self.window_size = window_size
self.rx_credits = window_size
self.rx_threshold = window_size // 2
self.tx_credits = window_size
self.rx_max_frame_size = rx_max_frame_size
self.rx_initial_credits = rx_initial_credits
self.rx_max_credits = RFCOMM_DEFAULT_MAX_CREDITS
self.rx_credits = rx_initial_credits
self.rx_credits_threshold = RFCOMM_DEFAULT_CREDIT_THRESHOLD
self.tx_max_frame_size = tx_max_frame_size
self.tx_credits = tx_initial_credits
self.tx_buffer = b''
self.state = DLC.State.INIT
self.role = multiplexer.role
@@ -478,7 +484,7 @@ class DLC(EventEmitter):
# Compute the MTU
max_overhead = 4 + 1 # header with 2-byte length + fcs
self.mtu = min(
max_frame_size, self.multiplexer.l2cap_channel.peer_mtu - max_overhead
tx_max_frame_size, self.multiplexer.l2cap_channel.peer_mtu - max_overhead
)
@property
@@ -645,9 +651,9 @@ class DLC(EventEmitter):
cl=0xE0,
priority=7,
ack_timer=0,
max_frame_size=self.max_frame_size,
max_frame_size=self.rx_max_frame_size,
max_retransmissions=0,
window_size=self.window_size,
initial_credits=self.rx_initial_credits,
)
mcc = RFCOMM_Frame.make_mcc(mcc_type=MccType.PN, c_r=0, data=bytes(pn))
logger.debug(f'>>> PN Response: {pn}')
@@ -655,8 +661,8 @@ class DLC(EventEmitter):
self.change_state(DLC.State.CONNECTING)
def rx_credits_needed(self) -> int:
if self.rx_credits <= self.rx_threshold:
return self.window_size - self.rx_credits
if self.rx_credits <= self.rx_credits_threshold:
return self.rx_max_credits - self.rx_credits
return 0
@@ -749,7 +755,7 @@ class Multiplexer(EventEmitter):
connection_result: Optional[asyncio.Future]
disconnection_result: Optional[asyncio.Future]
open_result: Optional[asyncio.Future]
acceptor: Optional[Callable[[int], bool]]
acceptor: Optional[Callable[[int], Optional[Tuple[int, int]]]]
dlcs: Dict[int, DLC]
def __init__(self, l2cap_channel: l2cap.ClassicChannel, role: Role) -> None:
@@ -761,6 +767,8 @@ class Multiplexer(EventEmitter):
self.connection_result = None
self.disconnection_result = None
self.open_result = None
self.open_pn: Optional[RFCOMM_MCC_PN] = None
self.open_rx_max_credits = 0
self.acceptor = None
# Become a sink for the L2CAP channel
@@ -869,9 +877,16 @@ class Multiplexer(EventEmitter):
else:
if self.acceptor:
channel_number = pn.dlci >> 1
if self.acceptor(channel_number):
if dlc_params := self.acceptor(channel_number):
# Create a new DLC
dlc = DLC(self, pn.dlci, pn.max_frame_size, pn.window_size)
dlc = DLC(
self,
dlci=pn.dlci,
tx_max_frame_size=pn.max_frame_size,
tx_initial_credits=pn.initial_credits,
rx_max_frame_size=dlc_params[0],
rx_initial_credits=dlc_params[1],
)
self.dlcs[pn.dlci] = dlc
# Re-emit the handshake completion event
@@ -889,8 +904,17 @@ class Multiplexer(EventEmitter):
# Response
logger.debug(f'>>> PN Response: {pn}')
if self.state == Multiplexer.State.OPENING:
dlc = DLC(self, pn.dlci, pn.max_frame_size, pn.window_size)
assert self.open_pn
dlc = DLC(
self,
dlci=pn.dlci,
tx_max_frame_size=pn.max_frame_size,
tx_initial_credits=pn.initial_credits,
rx_max_frame_size=self.open_pn.max_frame_size,
rx_initial_credits=self.open_pn.initial_credits,
)
self.dlcs[pn.dlci] = dlc
self.open_pn = None
dlc.connect()
else:
logger.warning('ignoring PN response')
@@ -928,7 +952,7 @@ class Multiplexer(EventEmitter):
self,
channel: int,
max_frame_size: int = RFCOMM_DEFAULT_MAX_FRAME_SIZE,
window_size: int = RFCOMM_DEFAULT_WINDOW_SIZE,
initial_credits: int = RFCOMM_DEFAULT_INITIAL_CREDITS,
) -> DLC:
if self.state != Multiplexer.State.CONNECTED:
if self.state == Multiplexer.State.OPENING:
@@ -936,17 +960,19 @@ class Multiplexer(EventEmitter):
raise InvalidStateError('not connected')
pn = RFCOMM_MCC_PN(
self.open_pn = RFCOMM_MCC_PN(
dlci=channel << 1,
cl=0xF0,
priority=7,
ack_timer=0,
max_frame_size=max_frame_size,
max_retransmissions=0,
window_size=window_size,
initial_credits=initial_credits,
)
mcc = RFCOMM_Frame.make_mcc(mcc_type=MccType.PN, c_r=1, data=bytes(pn))
logger.debug(f'>>> Sending MCC: {pn}')
mcc = RFCOMM_Frame.make_mcc(
mcc_type=MccType.PN, c_r=1, data=bytes(self.open_pn)
)
logger.debug(f'>>> Sending MCC: {self.open_pn}')
self.open_result = asyncio.get_running_loop().create_future()
self.change_state(Multiplexer.State.OPENING)
self.send_frame(
@@ -1039,15 +1065,13 @@ class Client:
# -----------------------------------------------------------------------------
class Server(EventEmitter):
acceptors: Dict[int, Callable[[DLC], None]]
def __init__(
self, device: Device, l2cap_mtu: int = RFCOMM_DEFAULT_L2CAP_MTU
) -> None:
super().__init__()
self.device = device
self.multiplexer = None
self.acceptors = {}
self.acceptors: Dict[int, Callable[[DLC], None]] = {}
self.dlc_configs: Dict[int, Tuple[int, int]] = {}
# Register ourselves with the L2CAP channel manager
self.l2cap_server = device.create_l2cap_server(
@@ -1055,7 +1079,13 @@ class Server(EventEmitter):
handler=self.on_connection,
)
def listen(self, acceptor: Callable[[DLC], None], channel: int = 0) -> int:
def listen(
self,
acceptor: Callable[[DLC], None],
channel: int = 0,
max_frame_size: int = RFCOMM_DEFAULT_MAX_FRAME_SIZE,
initial_credits: int = RFCOMM_DEFAULT_INITIAL_CREDITS,
) -> int:
if channel:
if channel in self.acceptors:
# Busy
@@ -1075,6 +1105,8 @@ class Server(EventEmitter):
return 0
self.acceptors[channel] = acceptor
self.dlc_configs[channel] = (max_frame_size, initial_credits)
return channel
def on_connection(self, l2cap_channel: l2cap.ClassicChannel) -> None:
@@ -1092,15 +1124,14 @@ class Server(EventEmitter):
# Notify
self.emit('start', multiplexer)
def accept_dlc(self, channel_number: int) -> bool:
return channel_number in self.acceptors
def accept_dlc(self, channel_number: int) -> Optional[Tuple[int, int]]:
return self.dlc_configs.get(channel_number)
def on_dlc(self, dlc: DLC) -> None:
logger.debug(f'@@@ new DLC connected: {dlc}')
# Let the acceptor know
acceptor = self.acceptors.get(dlc.dlci >> 1)
if acceptor:
if acceptor := self.acceptors.get(dlc.dlci >> 1):
acceptor(dlc)
def __enter__(self) -> Self: